Why do professionals love the D800

I wouldn't be surprised if 90% of Nikon shooters who had a d700 + d3s in the last generation are going to upgrade to the D800 and then have to make a decision about the D4. I think the D800 is a no-brainer upgrade because it will give you full HD video, larger DR, massive resolution and costs half what a D4 would cost. The D4 is an upgrade to the D3S but I think the difference between the two is a lot smaller than the D700 vs D800. Some pros might find that the D800 opens up different income streams. They could, for example, shoot a sporting event normally but also shoot some more atmospheric pictures of the venue that they can sell as large prints.